By Marina Walker Guevara, Kate Willson, and Marcos Garcia Rey Of The International Consortium of Investigative Journalists

The rapid demise of Eastern Atlantic bluefin tuna, the source of prized sushi around the world, is due to a $4 billion black market and a decade of rampant fraud and lack of official oversight, according to Looting the Seas, a new investigation by the International Consortium of Investigative Journalists.

As regulators gather in Paris this month to decide the fate of the threatened bluefin, ICIJ's investigation reveals that behind plummeting stocks of the fish is a supply chain riddled with criminal misconduct and negligence, from fishing fleets to sea ranches to distributors.

Each year, thousands of tons of fish have been illegally caught and traded, the seven-month investigation found. At its peak - between 1998 and 2007- this black market included more than one out of every three bluefin caught, conservatively valued at $400 million per year.

"Everyone cheated," said Roger Del Ponte, a French fishing captain. "There were rules, but we didn't follow them."

The Eastern Atlantic bluefin, whose spawning stock has plummeted nearly 75 percent since 1974, is prized by sushi lovers for its soft, red flesh. One large fish can fetch more than $100,000 in Japan, which consumes around 80 percent of the global bluefin market. The widely hunted bluefin has also become a bellwether, the latest threatened species in a feeding frenzy that has seen the disappearance of as much as 90 percent of the ocean's large fish.

Led by the French, Spanish, and Italians, joined by Turks and others, Mediterranean fishermen violated official quotas at will and engaged in an array of illegal practices: misreporting catch size, hiring banned spotter planes, catching undersized fish, and plundering tuna from North African waters where EU inspectors are refused entry. An illicit market even arose in trading quotas - when regulators finally started enforcing the rules - in which one vessel sells its nation's quota to a foreign vessel that had overfished.
The bluefin black market is not a surprise to some experts. "Fisheries are one of the most criminalized sectors in the world," said Daniel Pauly, a marine biologist at the University of British Columbia, who was one of the earliest voices to warn the world about the impact of commercial fishing on marine ecosystems. "This generates so much money that it's like drugs."

This black market has been abetted by a host of officials, from overworked local inspectors to international regulators - most notably the International Commission for the Conservation of the Atlantic Tunas (ICCAT), a regulatory body set up to protect the bluefin stocks, which frequently ignored its own scientists' recommendations for smaller fishing quotas and tighter controls.

"There was just no political will to enforce the rules, most notably the quota," said Jean- Marc Fromentin, a marine biologist and a member of ICCAT's scientific body. "Until 2008... there was no enforcement. No one declared. There was general cheating."

On November 17, ICCAT member countries will gather in Paris to decide on a host of recommendations in the hope of preserving the fish from collapse, including a possible moratorium on industrial bluefin fishing.

Biologists warn that at stake is more than the mere loss of a favorite source of sushi. Bluefin tuna, they say, are near the top of the food chain and their demise will have dire consequences for marine ecosystems. Without large predators, entire food chains may erode, leaving the seas overrun by millions of jelly fish and micro-organisms.